Rustproofing



April 6, 1954 M. J. sHNlTzLER RUSTPROOFING Filed July 19 1950 Si QM mm2@ #.rwtlllfllllllllllrll 'Lr (1h.

ATTOR/l/EP Patented Apr. 6, 1954 RUSTPROOFING Meyer J. Shnitzler, Brookline, Mass., assignor to The Gillette Company,

ration of Delaware Boston, Mass., a corpo- Application July 19, 1950, Serial No. 174,662

3 Claims.

My invention concerns a method of treating ferrous metal objects to prevent or reduce corrosion thereof and has particular reference to the rust-proofing of steel razor blades.

'Ihe tendency of steel razor blades to corrode has presented a serious problem to blade manufacturers. For many years it has been standard practice to coat the individual blades (or the Where the blades are lacquered) with an anti-rust oil. When the blades are individually wrapped, this procedure is reasonably effective as to temperate climates if unusual conditions are not encountered, but affords inadequate protection in tropical countries, where conditions of high temperature and high relative humidity prevail, the corrosion being most pronounced if the blades are stored, as is most usual, in the acidic atmosphere of'a typical home medicine cabinet. l/Vhen the blades are not individually wrapped, as is true, for instance, in the case of the dispenser type packages currently in vogue, the protection provided by anti-rust oils as presently compounded is insuicient even for temperate climes-here, again, especially where blades are exposed to the atmosphere of a home medicine cabinet.

In accordance with the present invention, I dispense with the oil film entirely or I supplement its action by first treating the blades with a volatile compound capable by reaction with the raw metal surfaces of the blades of pro-viding a rust-inhibiting film thereon. Depending on the degree of protection required, I may subsequently package the blades, as disclosed in copending application, Serial No. 174,664 led July 19, 1950, in a container incorporating a compound which, in the environment of a typical home medicine cabinet, is capable of continuing gir supplementing the rust-preventing protec- The volatile compound which I prefer for employment in my process is benzoic acid, but salcylic or phthalic acid, for example, may be used In these cases, the film is composed of an iron salt of the acid.

According to the invention, the compound in its volatilized form is brought into contact with the blades or other articles in company with water vapor, used as a carrier for the volatilized material. In the case of the above named acids, the water vapor has been found to promote the reaction between the compound and the ferrous metal giving the protective film.

I shall further describe my invention with reference to the accompanying drawing which (Cl. 14S-6.35)

illustrates in essentially diagrammatic fashion a system of apparatus suitable for carrying out the method of the invention.

In the drawing, the numeral I 0 denotes a pressure-tight generator or still of sylindrical cross section having a jacket I2 of insulating material. A screen I4 is suitably supported within the vessel in spaced relation to the bottom thereof, the screen serving as a holder for the volatile compound, preferably benzoic acid as indicated. The supply of acid may be replenished as necessary through the door I6.

Heating means, shown as an electric heater i8, serves to vaporize the water, supplied as required via line 20. 'Ilhe mixture of water vapor and volatilized acid is conveyed, via insulated line 2t, to a cabinet 26 which is under a lower perssure than that prevailing in the generator. The cabinet is provided with a line 28 extending to an exhaust pump, not shown, and with a door 30, 32 at each end thereof, the doors being respectively inwardly and outwardly swingable. The blades 34 to be rust-proofed, are conveyed through the cabinet on a belt 38 traveling between the distributor cone 35 and the collection cone 36, the blades being carried on trays 40. The latter are each provided with a pair of rails 42 acting as cams with respect to the doors 30 and 32. To avoid possible adverse channeling of the vapors, both the trays and the belt may be suitably perforated. Blades 34 are supported on the trays by holders 44, the disposition of the blades being such that contact of the volatilized acid with both of the honed edges is assured. Where the blades are not double-edged they may be fitted in slots in the trays.

If desired, transport of the mixed vapors to the cabinet may be hastened by means of a gas, as air or nitrogen, introduced below the level of the water in the vessel I0.

In still another method of operation, the water bath is dispensed with and a mixture of steam and a diluent gas, as air or nitrogen, is introduced under the screen supporting the acid through the line 20.

Operating as indicated by the drawing, I prefer to maintain the Water at a temperature around F. The pressure in the cabinet 26 may be about one inch of water above atmospheric pressure, for example.

From the foregoing, it is believed evident that my invention supplies a method for rust-proofing razor blades which is economical in execution and which can be readily integrated with other factory procedures. It should not, of

3 course, be taken that the invention is limited to the treatment of razor blades, for it can be otherwise applied to great advantage.

I claim:

1. Method of rust-proofing steel razor blades comprising contacting the same with an acid from the group consisting of benzoic, salicylic and phthalic acids, the acid being brought into contact with the blades as a vapor in company with water vapor.

2. Method of rust-proofing steel razor blades comprising contacting the blades with Vaporized benzoc acid in the presence of Water vapor.

3. Method of rust-proofing ferrous objects comprising contacting the same with an acid from the group consisting of benzoic, salicylic and phthalic acids, the acid being brought into contact With the object as a vapor in company with Water vapor.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date Panton Feb. 4, 1873 Conradson Jan. 27, 1885 Bower et al. Oct. 25, 1904 Bontempi Mar. 10, 1908 Rees Feb. 15, 1910 Smith Dec. 19, 1911 Carnahan June 1, 1915 Donchi May 16, 1939 FOREIGN PATENTS Country Date Great Britain Dec. 30. 1940 

3. METHOD OF RUST-PROOFING FERROUS OBJECTS COMPRISING CONTACTING THE SAME WITH AN ACID FROM THE GROUP CONSISTING OF BENZOIC, SALICYLIC AND PHTHALIC ACIDS, THE ACID BEING BROUGHT INTO CONTACT WITH THE OBJECT AS A VAPOR IN COMPANY WITH WATER VAPOR. 